This invention relates to a device for and methods of determining the dynamic lie of a golf club and to a target object used therewith and particularly relates to a device for and methods of determining the "toe up" and "toe down" conditions associated with a golfers swing and, further, to the structure of a target object used with the device and in the practice of the methods.
In the playing of the game of golf, a golfer uses a golf club to strike a golf ball and drive the ball through a flight trajectory. The club includes a shaft having a club head at a lower or tip end of the shaft and a grip at an upper or butt end of the shaft. The club head is secured to the tip end of the shaft and typically extends at a near right angle from the tip end. The club head further includes a club face which is the impact surface which the golfer moves into engagement with the golf ball when the club is swung by the golfer. The club face typically includes a series of spaced, parallel lines or grooves formed therein which are generally parallel with the bottom edge of the club face.
In playing the game of golf, it is desirable for the golfer to swing the club in such manner that the bottom of the club head and the lines or grooves on the face of the club are parallel to the plane of a surface on which the golf ball is situated. Generally, when the ball is struck by the face of the club head which is in this planar alignment, the ball will travel through a trajectory in a path selected and desired by the golfer. The position of the club head relative to the plane of the surface on which the golf ball rests at the instant the club face strikes the ball is commonly referred to as the "dynamic lie" of the club.
Frequently, when a golfer swings a club, the golfer may not be holding the club in the appropriate manner and the free end, or toe end, of the club head may be undesirably pointing downward, a "toe down" condition, or upward, a "toe up" condition. In any event, when a ball is struck by a club head which is in such a "toe down" or "toe up," the ball spins improperly and is launched in such a manner that the ball veers to the right or the left of the trajectory desired by, and the intended aim of, the golfer. Under these conditions, the unwanted effects of the improper dynamic lie of the club can be quite significant.
It is thus incumbent upon the golfer to determine that a "toe up" condition or a "toe down" condition exists and the degree of such condition. Only then can the golfer take the corrective measures necessary to enhance the golfers playing of the game.
One technique used to determine whether a "toe up" condition or a "toe down" condition exists involves the use of an artificial ground board on which a scuffing material is located. A golf ball is placed on the surface and an adhesive backed paper is adhesively secured to the bottom of the club head. The golfer then swings the club to hit the ball. If the club head is in a perfect position to the strike the ball, the bottom of the club, and the paper adhered thereto, will scrape the ground board generally on the center of the bottom of the head, thereby making scuff marks on the paper at this location. The so-located scuff marks provide an indicator that the golfer is holding and controlling the club properly when the club strikes the ball.
If the toe end of the club head is tilted downward or upward, the scuff marks will appear at a forward portion or a rearward portion, respectively, of the paper which is adhesively secured to the bottom of the head. This result provides an indication to the golfer that, when the head engages the ground board, the club is in a "toe down" or a "toe up" condition and a swing correction is necessary. This technique provides a relationship between the lie of the club head and the ground board but does not necessarily provide a relationship between the dynamic lie of club at the instant it strikes the golf ball. Depending on the manner in which the golfer is manipulating the club during the swing, significant changes can occur immediately before the club head strikes the ball which the above-described technique using a ground board would not detect.
Thus, there is a need for a device and a method for determining in a dynamic context the lie of the club at the instant that the club head strikes the ball.